Air-pressure grease gun



J. w. WELCH ET An.-

Uct. 26 9 1926.

AIR PRESSURE GREASE GUN 2 Sheets-Sheet 1' Invenfora. (75.12286 W W'elc/z dlzd' Gerald 6 Rqg'ez's.

new Alfarneys.

' Oct v r J. w. WELCH ET AL AIR PRESSURE GREASE G UN Ei led August 1 1325 2 Sheets-Sheet 2 Patented Get. 26, 1926.

UHTED STATES PATENT JAMES W. "WELCH AND GERALD S. ROGERS, OF LOS ANGELES, CALIFORNIA.

AIR-PRESSURE GREASE GUN.

Application filed August 1, 1925. Serial No. 47,498.

An object of this invention is to provide an air pressure grease gun that is adapted to efficiently force a body of lubricant through an outlet passage with means in 5 connection therewith for increasing or decreasing the air pressure so that the lubricant can be automatically forced into grease cups, receptacles and bearings.

, Another object is to provide a portable 'grease gun that is easily manipulated to force heavy lubricants under high, low or intermediate air pressure through a passage that is controlled by a plunger valve with means in connection with the plunger for manually boosting the flow of lubricant after it has entered the passage.

Another object of the invention is to provide a grease gun having a floating piston that can be driven by compressed air against a. charge of grease to discharge it from the gun with means in connection therewith for releasing "the air pressure on the dpiston, whereby the gun can be recharge with grease, and in this respect the invention is broadly new.

Another object is to provide a grease gun having a free piston that is constructedand arranged so as to form a movable partition between the grease and air chambers that is impervious to leakage.

Another object is to provide a portable grease gun that is neat and pieasin in appearance; easy to construct, assem le and operate; and that is durable in use.

Features of invention are shown in the construction, combination and arrangement of the parts whereby a grease gun 1S rovided that is light to handle and very e cotive in action.

Uther objects, advantages and features of invention may a pear from the accompany ing drawings, t e subjoined detailed de scription, and the appended claims.

The accompanying drawings illustrate the invention.

Figure 1 is a side view of an air pressure rease gun constructed in accordance with this invention, showing by dotted lines an ah tered position of the air pppisten red and hand knob; Fig. 2 is a fragmental central longitudinal section through the discharge end of the grease gun as indicated by line 22, Fig.3, showing the discharge passage closed; Fig. 3 is a plan view of the discharge end of the grease gun Fig. 4 is a 65 fragmental central longitudinal section analogous to Fig. 2 showing the discharge passage open; Fig. 5 is a central lon itudinal section through the grease gun on ine 55 of Fig. 1; Fig. 6 is a fragmental central section through a portion of the gun cylinder with an inverted lubricant container arranged end to end thereon; showing a pre ferred means for loading the gun; Fig. 7

is a fragmental sectionalview analo ous to Fig. 6, showing the lubricant disc arged from the container into the gun; Fig. 8 is a perspective view of a movable false bottom to the container that is adapted to he forced from the bottom to the open end of the container to transfer the heavy lubricant from the container to the n.

The gun 10 has a hollow cylinder 11 that has its ends closed by the screw caps 12 and 13L The screw cap 12 is detachable from the cylinder so that it can be removed when th'e' gun is to be 'loaded with a lubricant; and the ca 13 is preferably secured in place by a so der seal 14: to compressed air from the gun.

A free piston 15 is arranged in the'cylinder 11 so as to separate its interior into a lubricant chamber 16 and an air chamber 17. Preferably the free piston 15 comprises a 85 center disk plate 18 on opposite sides of which are arranged fibrous aching 19, 20 that are provided with cylin rical skirts 21,

22 that extend in opposite direction in the cylinder 11. W A. relatively heavy metal flanged disk 23 is fitted over the packing l9, and a metal dish 2% having a long cylindrical skirt 25 is fitted against the packing 20, and these parts are secured together by a center screw 26.

By this construction and arrangement of the parts a packed free piston is provided that can be treaty movedin the cylinder but prevent the escapement of which is impervious to an escapement of grease or air between it and the inner wall of the cylinder.

Normally the piston 15 engages extensions 27 on an air valve housing 28 that is threaded into the discharge end of the pump cylinder 29. The housing 28 is provided with a spring pressed air valve 30 that is adapted to open when air is forced toward it with more pressure than has the air in the air chamber 17..

The pump cylinder 29 is screwed into a threaded boss 31 centrally arranged and integral with the cap 13; and this cylinder is also provided with an annular flange 32 that is adapted to pinch the packing ring 33 against the-cap 13 and thereby prevent air leakage from the chamber 17.

The pump cylinder 29 has a cap 34 screwed onto its inlet end to form a guide 44 for the piston rod 35 that connects the hand knob 36 with the pump piston 37.

The piston 37 is constructed so that it functions both as a piston and an inlet valve asair is arranged to pass between the outer wall of the piston and the inner wall of the pump cylinder when the piston is moved toward the cap 34.

In other words the piston has a packing 38 secured between the opposing disks 39, 40 and nuts 41, 42 on the inner threaded end of the rod 35. The disks 39, 40 are of less a diameter than the inner diameter of the cylinder 29, and the packing 38 is provided with an elongated cylindrical skirt 43 that is adapted to be forced outward against the inner wall of the pump c linder by air trapped between the piston 37 and the valve 30 when the piston is forced toward the valve or moved on its inner stroke; and the skirt 43 can yield sufiicient on the outer stroke of the piston for air to pass between it and the inner wall of the cylinder to thereby supply a charge of air for compression when the piston is actuated inwardly.

A slight clearance is provided between the rod 35 and guide 44 so that air can freely enter the inlet end of the pump cylinder.

The cap 12 as previously stated is detachably connected to the discharge end of the cylinder 11 and preferably a packing ring 45 is interposed between the end of the cylinder 11 and cap 12 to prevent leakage.

The cap 12 is provided with an integral housing 46 that has a cylindrical bore 47 that extends crosswise of the cylinder 11 and which is connected thereto by a port 48, and the bore 47 is connected with a passage 49 that is adapted to function as the discharge outlet of the gun.

The passage 49 extends through an internally threaded cylindrical stem 50 to which can be attached a pipe connection 51.

The pipe COI1I18Ctl0l1 51 can be of any standard flexible type such as are commonly in use with grease guns. As such pipes are well understood in the art the pipe connection 51 is not shown and described in detail.

A plunger 52 is closely fitted into and adapted to be reciprocated in the bore 47 so that it can be moved to close or open the port 48 or function as a valve; and also, so that it can be forced with great ressure toward the passage 49 to boost the ow of lubricant through the passage. I

The plunger 52 is pivotally connected by a pin 53 to a hand lever 54.

The lever 54 has its short end 55 pivotally connected by a pin 56 to the outer ends of a pair of rock arms 57; the inner ends of which are pivotally connected by a pin 58 to a post 59 that is integral with the housing 46.

The gun 10 is shown in 5 charged to full capacity and the preferred method of loading the gun is shown in Figs. 6 to 8 inelusive.

A valve screw 60 is adjustable in a boss 61 that is integral with the bottom of the cap 13; and this valve is normally closed. It is opened to release the compressed air through the bypass 62; so that the free piston 15 can be returned to a normal position when the gun is to be recharged with a lubricant.

When the gun is to be recharged, the cap 12 is removed so that a lubricant container 63 can be inverted and its open discharge end inserted into the open end of the cylinder 11 and seated on inwardly extending lugs 64 that are integral with the cylinder 11.

The container 63 is provided with a perforated bottom 65 that has a soft metal covering 66 soldered over the perforation 67.

The covering 66 is removable or adapted to be torn away when the contents of the container are to be forced into the cylinder 11; so that an appliance, preferably a cylindrical pointed rod 68 can be inserted through the opening 67 to force the false bottom 69 of the container toward the cylinder 11 to thereby transfer substantially all of the lubricant 70 from the container to the gun.

Preferably the false bottom 69 is a hollow cone having a base edge fitted snugly to the inner cylindrical wall of the container so that when it is forced from the bottom to the top of the container it will discharge substantially all of the contents therefrom. Also the false bottom 69 is conical and hollow so that the point of the rod 68 can be seated in'the apex of the cone :1 considerable distance in advance of its frustum 71; and so that the pressure to force the false bottom from end to end of the container will be centralized so that the false bottom will not be displaced sidewise.

The container 63 is formed to fit into the end of the cylinder 11 as stated; and its capacityis substantially the capacity of the chamber 16 when the piston 15 is seated on the extensions or at its limit of movement toward the air chamber; so that the contents of the container willfully charge or recharge the gun 10.

In operation the gun is charged with a lubricant as stated and then the ca 12 is secured in place so as to prevent lisaka e at the discharge end of the gun. Then t e air pump is actuated to charge the chamber 17 with air at a desired pressure. The desired pressure can be estimated by the resistance to the piston 37 on its inward stroke; or if desired the n can be rovided with a gauge not s own but w ich is well understood in the art.

When the chamber 17 is sufiiciently char ed with air the pipe connection 51 is fitte to the cap, container or bearing to be lubricated and then the hand lever 54 is actuated to ppen the port 47, so that the lubricant 70,"which preferably is heavy oil,

will be automatically forced to points useding lubrication by means of the compressed air in the chamber 17 forcing the free piston 15 toward the discharge end of the gun. It is understood that the. air pressure in the chamber 17 can be suflicient to force the piston 15 from its normal position to the discharge end of the gun or until it has forced all of the lubricant out of the chamber 16. As previously stated the hand lever 54 can be actuated to boost the lubricant after it has passed out of the port 48; or it can be used to reciprocate the plunger 52 so that it functions simply as a valve.

lVe claim: Y

1. A compressed air grease gun including a cylinder having a discharge end; lugs ,floating piston to discharge the a check valve construction in the inner end" construction havin within said gun for applying airipressure to discharge a lubricant from said cylinder.

2. A compressed air grease gun includ ing a cylinder having a discharge end and adapted to be charged with a lubricant; internally extending lugs integral with said cylinder and arranged adjacent the discharge end thereof that are a seat on which the open end of a container can be seated when said cylinder is to. be charged with a lubricant; andmeans within said gun for applying air pressure to discharge a lubricant from said cylinder.

3. A compressed air grease compris ing a main cylinder adapte to contain grease, a floating piston in said cylinder for discharging the grease and providing an air chamber in the end of the cylinder opposite the end thereof that contains the grease, an air pum cylinder'extending centrally and longitu inally into the air chamber end of the main cylinder, a iston and piston rod in said air pump for orcing air into said air chamber for actuating the of said air pump cylinder, said check valve air'passage throug itand an annular extension surrounding the air passa e for preventing the floating piston from closing and interfering with such air passage.

In witness whereof, we have hereunto affixed our signatures.

JAMES W. W'ELCH. GERALD S. ROGERS.

adapted to form grease, and

a central valve closed 

